1. Field of the Invention
This invention relates generally to spraying apparatus and more specifically to spraying apparatus which can be carried by an aircraft.
2. Description of the Prior Art
In the past various spraying apparatuses have been carried by aircraft, such as helicopters, to spray fluids such as liquid fertilizer or insecticides over a relatively large area of vegetation. These spraying apparatuses have typically included a tank providing a reservoir for the fluid and a spray boom extending laterally of the tank to conduct fluid to the atmosphere. Boom support members have been used to aid in supporting the weight of the spray boom.
In one type of spraying apparatus, the tank is suspended far below the helicopter by a flexible cable which is releasably supported by a hook beneath the helicopter. Because the tank is far below the helicopter, it is difficult for the pilot to accurately determine the position of the tank. In other words, pilot depth perception problems are created. In addition the flexible cable permits the spraying apparatus to swing beneath the helicopter. This, of course, affects not only the stability of the helicopter but also the accuracy with which a given area can be sprayed.
One advantage of considerable importance, however, is that this type of spraying apparatus can be released even while the helicopter is in flight by merely opening the hook. This can be particularly desirable from a safety standpoint if the helicopter becomes endangered. A release capability is also desirable since it permits the helicopter to be flown separately of the spraying apparatus.
In another type of spraying apparatus, the tank is permanently fixed to the helicopter. The spray boom typically extends from the tank and the boom support members extend between the helicopter and the spray boom. This type of spraying apparatus has a fixed relationship with the helicopter when in flight and therefore does not have a particularly adverse affect upon the stability of the helicopter. One disadvantage of this type of spraying apparatus is that only the contents of the tank can be dumped and the spraying apparatus can not be jettisoned. Thus, if the helicopter is "in trouble" the spraying apparatus imposes an undesirable weight penalty. In addition, if the helicopter must make a forced landing, the long, laterally extending booms prevent the helicopter from being landed in a relatively small area.